The purpose of the research is to gain insight into the control of renin in the adrenal medulla. the function of extra-renal renin is unknown. The highest concentration appears to be in the adrenal medulla. The methods to be used are similar to those used in the study of the cellular physiology and pharmacology of catecholamine secretion. They include studies on the subcellular distribution of renin and an analysis of the factors which may affect its release from the adrenal gland. Agents to be used on the perfused bovine adrenal gland will be those known to affect renin release from the kidney as well as those known to affect catecholamine release. The angiotensin-generating activity in the adrenal medulla will be compared to that in the renal cortex. Since renin is one of the humoral regulators of the cardiovascular system, an understanding of its control in extra-renal tissues should aid in an understanding of physiological and pathologial conditions. Bibliographic references: Renin and pseudorenin in rat and bovine tissues. Alan M. Poisner, Jau-Shyong Hong and Joseph Bernstein. Proc. 57th Endocrine Soc. Meeting, New York, p 309, 1975. Renin and pseudorenin in bovine kidney, spleen and adrenal medulla. Alan M. Poisner, Jau-Shyong Hong and Joseph Bernstein. Proc. 6th International Congr. Pharmacology, Helsinki, 1975.